Polish Spanish localization in Sparkle.strings (#2875)

Changes include:
- 'corriendo' -> 'ejecutando'
- '¿Quisieras' -> '¿Querrías' (two strings)
- add accent in 'sólo' (read-only)
- 'Ready to Install' translation adjusted to feminine 'Lista para instalarse'
- 'póngase en contacto' -> 'ponte en contacto'. No English source keys were modified.